Light guides are devices used to transport light from a light source to a distant point with minimal loss. The light is transmitted through a light guide by means of internal reflection. Light guides are typically made of optical grade materials such as acrylic resin, polycarbonades, epoxies, silicones, and glass.
Typical uses for light guides include transmission of light from an LED lamp or a PC board to a front panel for status indication, collection and direction of light to backlight an LCD display or legend, and illuminating a grid pattern on a see-through window.
A typical light guide arrangement compromises a light source, such as a light-emitting diode placed at one end of the light guide. The light source is oriented such that the central light path is aligned with the main axis of the light guide.
A major drawback with this arrangement is that the ability to link the LED to a heat sink is severely limited by the space provided for the LED backlighting.
In the case of a multi LED light guide each LED is placed at one end of a light guide. Again the central light path is aligned with the main axis of the light guide.
In the prior art, the placement of the LED results in dark spots affecting the color and brightness of the light and in hot spots between the LEDs. In addition, as with the single LED light guide, the ability to transfer heat to a heat sink or similar device is limited.